USPTO Patents Application 10567929

wo 2005/018012

PCT/EP2004/008105

Claims

1. A photovoltaic device, comprising a composition of carbon nanotubes and/of at least one
organic compound acting as a hole conductor.

2- The device according to claim 1, characterized in that it further comprises

- a first electrode on one side of said composition of carbon nanotubes and of at least .
one hole conductor, said first electrode having a first work fimction, and

- a second electrode on another side of said composition of carbon nanotubes and of at
least one hole conductor, said second electrode having a higher work function thian
said first work function.

3. The device according to any of the foregoing claims, characterized in that said at least one
hole conductor is a conjugated polymer or a blend of at least two conjugated polymers.

4. The device according to any of the foregoing claims, characterized in that said carbon
nanotubes are a mixture of metallic and semiconducting carbon nanotubes, preferably
only semiconducting carbon nanotubes.

5. The device according to any of the foregoing claims, characterized in that said carbon
nanotubes are a nMxture of multi-walled and single-walled carbon nanotubes, preferably
only single-walled carbon nanotubes.

6. The device according to any of the foregoing claims, characterized in that the carbon
nanotubes have a diameter in flie range of firom 0.5 nm to 2 nm.

7. The device according to any of the foregoing claims, characterized in that the band gap of
said carbon nanotubes lies in the range of firom about 0.5 to about 1' eV.

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8. The device according to any of the foregoing claims, characterized in that the band gap of
said at least one hole conductor lies in the range of from about 1 eV to 3 eV, preferably
from about L5 eV to 2.5 eV, more preferably from about 1 .75 eV to 2.25 eV.

9. The device according to any of the foregoing claims, characterized in that^said hole con-
ductor is selected from die group comprising semiconducting organic materials v^Hi a
band gap above 1 eV and a u-orbital higher in energy than Hie highest occupied molecular
orbital (HOMO) of said carbon nanotubes.

10. The device according to any of the foregoing claims, characterized in that said composi-
tion of carbon nanotubes and of at least one organic hole conductor comprises a mixture
of carbon nanotubes and at .least one hole conductor.

11. The device according to any of claims 1-9, characterized in that said composition is a
two-layer-system, wherein said at least one hole conductor is in one layer and said carbon
nanotubes ard in anotiier layer.

12. The device according to any of claims 1-9, characterized in tiiat said composition is a
multiple-layer-system, wherein said at least one hole conductor and said carbon nanotubes
are in alternating layers.

13. The device according to any of claims 2-12, characterized in that said carbon nanotubes
have been vertically grown, preferably on one of said electrodes.

14. The device according to any of claims 2-13, characterized in that a hole conductor is di-
rectly grown on said carbon nanotubes ("overgrown nanotubes'O-

15. The device according to any of claims 2-12 and 14, characterized in that said carbon
nanotubes have been horizontally aligned, preferably on one of said electrodes.

16. The device according to any of the foregoing claims, characterized in that said at Jeast one
hole conductor is selected from the group comprising

polymethacrylates and derivatives, e.g. bis(diarylamino)biphenyl ftmctionalised
methacrylates and copolymers thereof.

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polyaniline and derivatives,
polyphenylene and derivatives,

polyphenylene vinylene and derivatives, e.g. poly(2-methoxy, .5-(3% 7*-
diniethyloctyloxy)-l,4-phenylene vinylene (MDMO-PPV),
polythiophene and derivatives,

copolymers of triphenyl diamine derivatives and trimethoxyvinylsilane,

poly(3,4-etiiylenedioxythiophene: polystyrene sulfonic acid) (PEDOTiPSS),

polyacetylene and derivatives thereof,

polyparaphenylene and derivatives thereof

polypyrrole and derivatives thereof,

polyparaphenylene sulfide and derivatives thereof,

polycarbazole and derivatives thereof,

polyisothianaphene and derivatives thereof,

poly(l,6-heptadiyne) and derivatives thereof, and

polyquinoline and derivatives thereof

17. The device according to any of claims 1-16^ characterized in that it is an organic solar
cell.

18. The device according to any of claims 2-17, characterized in that said first and/or said
second electrode is a film or layer of a transparent material.

19. The device according to any of claims 2 - 18, characterized in that said first or second
electrode is a metallic electrode.

20. The device according to any of claims 2-19, characterized in that said first and/or said
second electrode is coated with an evaporated layer of fluoride or acetate, e.g. LiF, CsF,
CHaCOOLi, or a combination of fluoride and acetate.

21. The device according to any of claims 18-20, characterized in that it additionally coin-
prises a solid inorganic crystalline or glassy substrate, or a metal foil substrate, preferably
a stainless steel foil substrate, or a polymer substrate pre-coated with said first or said sec-
ond electrode.

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22. The device according to any of claims 18-20, characterized in that it additionally com-
prises a flexible polymer substrate pre-coated with said first or said second electrode.

23. A combination of the device according to any of the foregoing claims with a circuit,
wherein the device according to any of the foregoing claims acts as an internal power
supply.

24. Use of the device accordmg to any of claims 1 - 22 as a solar cell.

25. A method of generating electricity from light, characterized in that a device according to
any of claims 1 - 22 or a combination according to claim 23 is irradiated by light, where-
upon a photo-initiated charge-separation process and subsequently a charge-transport pro-
cess occurs, and wherein further electricity is recovered from said device or from said
combination.

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